The Olympic Rain Forest is just a part of the global web of temperate rain forests found around the world. Several common factors link these forests together: 1 Mild, moist climate largely affected by the ocean 2 Multi-layered forest growing primarily needle-leaf trees 3 Abundant mosses, lichens, fungi and epiphytes 4 Large amounts of standing dead and fallen trees.

As moisture-filled clouds push inland, they release more than 12 feet of rain annually on the western slopes of the Olympic mountains. As elevation increases, more precipitation is released. On the east side of the Olympic Peninsula, the moisture-depleted clouds provide much lower rainfall, less than 20 inches per year in the "rain shadow."

Pacific Northwest is home to over 66% of the world's temperate rain forests.

Bogachiel Valley, Hoh Valley, Queets Valley and Quinault Valley are the Rain Forest "fingers" that reach from the coast inward into the mountains.